Fermi´s golden rule, nonequilibrium electron capture from the wetting layer, and the modulation response in P-doped quantum-dot lasers

Electron capture from a quantum dot´s (QDs) wetting layer is described by Fermi´s golden rule that relates the transition rate to the density of final states. The wetting layer capture causes a brief nonequilibrium electron distribution between the QD ground state and its wetting layer states and can slow a QD laser´s modulation response. This effect is studied for time constants and capture conditions relevant to self-organized InAs QDs. It is shown that even a moderately fast electron capture consistent with present low temperature measurements can limit a QD laser´s modulation speed.